Question from Sarah Knight:

My Scottie has horrendous breath, teeth are fine, have changed her diet, she also has charcoal on her meals, any other ideas truly welcomed!

Answer: Bad Breath

Hi Sarah, thanks for your question about your dog’s bad breath. To answer it, I’m going to run through the possible causes of halitosis, along with any other symptoms they might show. I’ll then talk about the most likely reasons, and where to go next with diagnosis and treatment options.

Causes of Halitosis

Halitosis, or “bad breath”, is defined as an “offensive odour emanating from the oral cavity”. There are a number of possible causes, some of which are more common than others.

1) Diet

You say you’ve modified her diet, but a lot of dogs (especially terriers!) eat unpleasant things given half a chance – particularly faeces (those of other dogs, horses, livestock etc), or dead and rotting things (often mice or birds found lying in the undergrowth when out on walks). Inevitably, eating anything like this will lead to bad breath.

2) Metabolic disease

We’re particularly talking about diabetes or kidney failure here – both of which can lead to halitosis. In diabetes, the body produces ketones as a fuel supply for the brain, which have a strong smell (with overtones of pear drops – however, not all humans have the gene required to be able to detect this); in kidney disease, the build up of nitrogen waste products in the blood may result in oral lesions and/or smelly breath. In both cases, you’d expect to see increased thirst and possibly weight loss, but the signs can be pretty subtle in the early stages.

3) Respiratory disease

Infections of the nose and sinuses often lead to foul smelling breath, as can tumours of the nasal cavity. Sometimes, in fact, there are no other symptoms, although I’d usually expect some nasal discharge (a single snotty nostril that doesn’t clear up is the classic sign). Have you noticed any wheezing or sneezing? These can be signs that there’s something amiss as well. Sometimes dogs can get foreign bodies such as grass blades stuck up their noses – these result in inflammation and infection, and the tell-tale smell.

4) Oesophageal disease

Some conditions of the oesophagus (the gullet or “food pipe”) can result in halitosis – particularly some tumours or a condition called megaoesophagus, where the gullet is stretched and doesn’t function properly. However, these are usually associated with regurgitation of food or difficulty swallowing.

5) Skin disease

Although I wouldn’t say it was especially common in scotties, infections of skin around the lips (lip fold pyoderma)  can occur in any breed, and can smell quite unpleasant – if the skin around her mouth looks sore or is painful, this is a distinct possibility that will need intervention. Pyoderma like this can also be a result of an allergic condition.

6) Dental disease

This is by far the most common cause of halitosis! Most dogs develop some tartar and plaque as they get older; in some its much worse than others. You say her teeth appear fine, and I’m sure they do, at least at the front; however, plaque is much more common towards the back of the mouth where it’s much harder to see. In addition, dogs can get what’s called a biofilm, where the teeth are covered in a thin membrane of bacteria, but may look normal. In addition, tooth disease doesn’t have to be above the gums – a healthy-looking tooth may have severe gingevitis (gum infection), or periodonitis (infection and inflammation of the roots) which is a common cause of bad breath.

I have to say that, without seeing her, I think some degree of dental disease is the most likely explanation.

Where do we go from here?

Firstly, it’s always worth checking to see if she is picking up faeces from something, and if so, preventing her from having free range in that area. If she’s eating her own, there are products available (e.g. Copro-Nil) that make a dog’s own faeces much less appetising.

Assuming that isn’t the (nice, simple!) cause, check to see if she is showing any other symptoms – snotty nose, sneezing, regurgitating, drinking more, losing weight etc. Measuring water intake over a 24 hour period is really useful; as a rough rule of thumb, more than 90ml per kg per day is an abnormally high amount. If she is showing any of these signs, or you are at all concerned, you should see your vet for further investigation. Blood and urine tests can be used to diagnose kidney disease and diabetes, and X-rays are commonly used for nasal and oesophageal disorders.

The next step is to check for dental problems. It is virtually impossible to do a full dental examination on a conscious patient, but your vet will probably have several tricks up their sleeve that let them get a good look around to pick up the obvious. For a full dental examination, however, an anaesthetic is needed (and I have to say, it’s pretty rare not to find any issues at all in an adult dog). A “dental” (so-called) is a very routine procedure, and would be my favoured way forward, unless you and your vet can be pretty confident that there aren’t any underlying dental issues.

What happens in a “Dental”?

Essentially, the dog is anaesthetised, then their mouth and teeth can be carefully examined (without risk to fingers). Any loose or diseased teeth are removed, and the remainder are scaled and polished to remove any plaque or tartar (just like a visit to the hygienist for us). Normally, the dog will go home the same day.

Is there anything else I can try first?

Yes – if there aren’t any other symptoms, and you can’t see any signs of gum disease or plaque, you can (and really should!) start brushing her teeth. In fact, even if your dog has just had a dental, if at all possible start to brush afterwards – bacteria attach to the freshly cleaned tooth within 6-8 hours, and mineralise (forming dental calculus or “plaque”) within days.

Get a soft tooth-brush suitable for her size (a children’s brush, or a specialist dog one), and some dog tooth-paste (DON’T use human paste – the mint flavour is really nasty for most dogs). Just as you would brush your teeth, gently brush hers, a little at a time until she gets used to it. I would strongly advise every dog owner to brush their pet’s teeth – it would avoid a lot of problems later on.

I hope that helps and that you can get her smelly breath under control!

David Harris BVSc MRCVS